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-   -   At or Below crossing restrictions on an RNAV departure (https://www.pprune.org/atc-issues/342907-below-crossing-restrictions-rnav-departure.html)

rspilot 12th Sep 2008 11:28

At or Below crossing restrictions on an RNAV departure
 
Was assigned an RNAV departure with cross at or below fix ABC at 7000 ft and then at or below fix XYZ at 9000. We than checked in with departure control and we were told to climb and maintain FL270.

I was of the understanding that you still must comply with the crossing restrictions, ABC at 7000 and XYZ at 9000, before we can climb and maintain FL270?

If this is true than what phraseology must ATC use to disregard the at or below crossing restictions?

Thanks for help with this,

RS

slatch 12th Sep 2008 13:31

In the US if the controller does not restate the previous restrictions they are cancelled and you are cleared unrestricted to FL270. I have heard some controllers make statements such as comply with previous restrictions then climb and maintain. It is not technically correct but conveys the idea. As a pilot and controller if I was issued that climb to FL270, I would read back "Nxxxx climbing unrestricted to FL270" Put it back on the controller to correct it if that is not what he/she meant.

rspilot 12th Sep 2008 14:09

Very good point. I will do that. The difficult thing is that the original clearance issued was " cleared to FL270, maintain
FL070" when asked for a clarification was told "climb via the published Departure Proceedure". After takeoff and checking in with departure we are instructed to "climb and maintain FL270".

Wish they would term it "recleared to climb and maintain FL270" to avoid confusion.

Pontius 12th Sep 2008 14:29

Apparently there are moves afoot to try and get rid of this ambiguity worldwide but, so far, not too much success. According the PANS-ATM Doc 4444, the basic idea is ATC should come up and say something along the lines of "Climb F350, level restrictions of the XYZ departure cancelled". As yet the USA, among others, has not adopted this change and has 'other procedures'.

I know it doesn't help your individual situation that much but, unless told otherwise, I believe we are required to follow the level restrictions on the SID.

Pera 13th Sep 2008 10:55


In the US if the controller does not restate the previous restrictions they are cancelled
IMHO this only applies when another requirement is issued. A clearance to climb is not a further requirement and it certainly doesn't apply to requirements on a SID.

IMHO the correct RT is ' cancel SID' or 'Cancel altitude requirements'.

slatch 13th Sep 2008 12:28

Believe me in my 26 years of air traffic control this has been discussed so many times .......If you really want a good idea on how big a deal it is read this

http://www.faa.gov/about/office_org/...007-01-274.pdf



But that being said every good controller I work with will hardly ever give a new altitude assignment if they want the aircraft to meet previous restrictions. We just wait until that happens and then reclear the AC. Much simpilier and no issues to explain.

But when I have my pilots hat on I always put the responsiability back on the controller by using a readback that states what I will do. If not corrected I have a good position to stand on if something comes up.

Z10 13th Sep 2008 12:51

From own experience, working in Norway.. if I told a pilot to climb to FL270, I would assume the pilot would climb by own discretion.
I could also add "..with no restrictions", if I knew that the usual procedure was blablabla XYZ 9000ft and so on.

If I want the pilot to comply with "earlier instructions", I would tell him to "when passing XYZ, continue climb to FL270",

Anyway.. the best way to solve it is for the pilot to ask if he/she should still comply with earlier instructions.

Jat Jet 14th Sep 2008 08:49

from Doc 4444
 
latest Edition of DOC 4444 specifies that in case of SIDs if your want aircraft to climb higher than the level prescribed in the SIDs or in case of STAR to descend aircraft below level specified in the STAR, the controller need to say that " Cancel level restriction of the SID/STAR and climb or descent to ____ level.
From the Mother doc
6.3.2.4 CLIMB CLEARANCE ABOVE LEVELS SPECIFIED IN A SID
When a departing aircraft on a SID is cleared to climb to a level higher than the initially cleared level or the level(s) specified in a SID, the aircraft shall follow the published vertical profile of a SID, unless such restrictions are explicitly cancelled by ATC.

6.5.2.4 DESCENT BELOW LEVELS SPECIFIED IN A STAR

When an arriving aircraft on a STAR is cleared to descend to a level lower than the level or the level(s) specified in a STAR, the aircraft shall follow the published vertical profile of a STAR, unless such restrictions are explicitly cancelled by ATC. Published minimum levels based on terrain clearance shall always be applied.

11.4.2.6.2.5 Level restrictions issued by ATC in air-ground communications shall be repeated in conjunction with subsequent level clearances in order to remain in effect.
I hope it makes things clear for both pilot and ATC:ok:

Pera 14th Sep 2008 23:13


6.3.2.4 CLIMB CLEARANCE ABOVE LEVELS SPECIFIED IN A SID
When a departing aircraft on a SID is cleared to climb to a level higher than the initially cleared level or the level(s) specified in a SID, the aircraft shall follow the published vertical profile of a SID, unless such restrictions are explicitly cancelled by ATC.

6.5.2.4 DESCENT BELOW LEVELS SPECIFIED IN A STAR

When an arriving aircraft on a STAR is cleared to descend to a level lower than the level or the level(s) specified in a STAR, the aircraft shall follow the published vertical profile of a STAR, unless such restrictions are explicitly cancelled by ATC. Published minimum levels based on terrain clearance shall always be applied.
This is what I would expect. The restrictions remain unless cancelled. I'm not sure why you would have published restrictions if you need to restate them.


11.4.2.6.2.5 Level restrictions issued by ATC in air-ground communications shall be repeated in conjunction with subsequent level clearances in order to remain in effect.
This is not how it's done where I am. A subsequent restriction cancels a previous one (unless restated), but a subsequent level clearance does not.

Important things to standardise.


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